Ship Wave-Induced Sedimentation of a Tidal Creek in Galveston Bay

Date

Jan.-Feb. 2008

Authors

Ravens, TM
Thomas, RC

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Abstract

During the summer of 2005, a tidal creek (Pine Gully) within a few kilometers of the Houston Ship Channel was completely blocked by a 200 m long and 1.5 m deep plug of silt and fine sand. This paper documents and explains this unusual sedimentation event. It then presents a new method for calculating ship wave-induced sediment transport into tidal creeks. Between November 2005 and January 2006, measurements of velocity, pressure, and suspended sediment concentration were taken in the creek approximately 150 m seaward of the plug. The data indicated ship wave-induced bores (one per ship). Each bore caused a net sediment transport of approximately 0.4 m super(3) toward the plug, enough to explain the observed rate of sediment accumulation. Cores of the plug showed that the plug material was consistent throughout, suggesting a single pathway (from the bay). During the period of plug formation, rainfall and creek discharge were relatively low indicating a likely factor for the plugging. Model calculations showed that significant ship wave-induced sediment transport into Pine Gully would occur only when Pine Gully mean depth is less than 0.8 m.

Description

pgs. 21-29

Keywords

channels, coastal oceanography, gullies, marine sediment cores, resuspended sediments, sedimentation, ships, waterways, wave forces

Citation